Can a Breastfeeding Mother Take Zofran (Ondansetron)?
Yes, breastfeeding mothers can safely take ondansetron (Zofran) without any waiting period or need to pump-and-dump, and breastfeeding can continue normally during treatment. 1, 2, 3
Guideline-Based Recommendation
The Association of Anaesthetists 2020 guideline explicitly lists ondansetron among anti-emetic medications that are compatible with breastfeeding, placing it in the same category as other commonly used drugs without special precautions. 1 This recommendation is based on:
- Pharmacokinetic principles that predict minimal transfer and infant exposure 2
- Clinical experience from perioperative use in lactating women 2
- Expert consensus from a major specialty society addressing medication safety in breastfeeding 3
No Restrictions on Breastfeeding
No waiting period is required before resuming breastfeeding after ondansetron administration, whether given intravenously or orally. 2, 3 The guideline applies to:
- Standard clinical doses used for nausea and vomiting management 2
- Both IV and oral formulations 2
- Acute management and perioperative settings 2
Supporting Evidence from Recent Research
A 2022 physiologically-based pharmacokinetic modeling study in 78 breastfeeding women provides quantitative safety data:
- Relative infant dose: 3.0% (well below the 10% safety threshold) 4
- Daily infant dose: 0.005 mg/kg/day 4
- The study concluded that "mothers receiving ondansetron can safely breastfeed" 4
This research validates the guideline recommendations with actual breast milk concentration data. 4
FDA Labeling Context
The FDA label acknowledges that ondansetron presence in human milk is unknown, but notes it is present in rat milk. 5 However, the label defers to clinical judgment: "The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for ondansetron tablets." 5
The guideline evidence supersedes the FDA's cautious "unknown" statement, as guidelines incorporate clinical experience and pharmacokinetic modeling that the FDA label lacks. 1, 2, 4
Important Maternal Safety Consideration
The primary caution with ondansetron relates to maternal cardiac safety (QT prolongation), not infant exposure through breast milk. 2 This is particularly relevant in mothers with underlying heart disease, but this concern applies to the mother's own safety rather than breastfeeding safety. 2
Clinical Bottom Line
Ondansetron is considered safe and compatible with breastfeeding according to current anesthesia guidelines. 3 Mothers can take ondansetron when clinically indicated for nausea and vomiting without interrupting breastfeeding, pumping-and-dumping, or delaying feeds. 2, 3